What do you think of my design? (Sander) ***UPDATE***

Padrig · Post by **Padrig** » Thu Jun 09, 2005 1:16 am

Well not MY design of course. Just borrowed many ideas and I have built a first mock-up. There will be a spring at the back for tension on the upper arm and a pivot for the idler wheel on top to adjust the tracking.

So, anything terribly wrong that you gentlemen can see?
I would also like to know if I should weld it or bolt it together. IÃ¢â‚¬â„¢ve read that bolting it together gives more freedom to adjust the angles. But IÃ¢â‚¬â„¢ve seen welded ones also.

Thanks for your help.

Pad

polarbearforge · Post by **polarbearforge** » Thu Jun 09, 2005 1:24 am

Looks good to me. I've seen that design and it does work.

I strongly suggest bolting it. I welded my first sander and it ended up being a better use of time to start over than to rebuild it.

Two possibilities for the bottom arm. You could mount the arm on a piece of square stock, and then slide it into a piece of square tubing and lock it in place. Or you could make the bottom arm pivot. Either way, you could lengthen or shorten the size of belts used.

Jamie

Alcyoneus · Post by **Alcyoneus** » Thu Jun 09, 2005 1:57 am

Belt size?

Padrig · Post by **Padrig** » Thu Jun 09, 2005 10:32 am

Thanks for the tip Jamie. I've seen your "sliding" arm on your site. I was tempted but I think I will make the first one with just one piece. I've sized it for 2X72 belts and as you said those are the most common. Keeping it simple for the first try is my goal. I will use the sliding arm thing on the next one, the one I have to build for my brother.

Alcy 2X72.

Pad

Trevor · Post by **Trevor** » Thu Jun 09, 2005 11:33 am

Nice-but it could be simplified if you wanted.

First off-the third wheel can be dispensed with. Put a large drive wheel on the motor and run it off that-that will give you enough clearance between the two sides of the belt.

As to adjusting the drift-that's what a mallet is for-seriously. Whacking the spring arm left or right will correct any drifting issues.

Otherwise-it will work the way you have it designed as is.

Padrig · Post by **Padrig** » Thu Jun 09, 2005 4:10 pm

Thanks Trevor. I wanted the 3 wheels design to get the motor further back since I wont be able to get a totally enclosed one. For dust control.

As to the tracking mallet, I am sure it would work but not as "classy".

Thanks for the tip though, in case I can't get it to work.

Pad

Halberds · Post by **Halberds** » Fri Jun 10, 2005 12:42 am

Hi Pad, My 2 cents.
I think the rubber coated work wheel should be higher if your bench is work height. The top idler adjust wheel looks a little small to me. It should be about 2.5" dia.with a machined tracking center crest. Sealed ball bearings are the best. Press fit. with extra press fit seals. 1/2" shaft machined with a nice flange to acomidate the adjuster, tracking and tension.

The belt will have to compress to get around such a small pulley, that shortens belt life. It will also be very fast, due to the reduction sizes. Divide it's diameter into the diameter of the motor wheel, that is the step up RPM ratio. That small wheel will be screaming.....

I would reposition the motor with about 24" between the drive and the contact wheel.

So far so good thanks for the progress pics.

Hal

Ps: I got me a Dewalt chopsaw now too.... What do you do with the sparks?

Padrig · Post by **Padrig** » Fri Jun 10, 2005 1:57 am

Hal, thanks for the tips. The top wheel is crowned but I will take your advice and make a larger one on the lathe.

I am not sure what you mean about the flange?

For the height, it will all be on an adjustable base like this so I will see what "feels" more confortable.

Again, thanks for your input.

Pad

Halberds · Post by **Halberds** » Fri Jun 10, 2005 2:26 am

The flange is part of the shaft that bolts on to the adjusting device. The spring loaded thing that lets you change belts with the pull of a leaver.

It also takes the load off the shaft and support bearings and provides a convenient mounting plane.

Best of luck little pilgrim...

Hal

Halberds · Post by **Halberds** » Fri Jun 10, 2005 3:11 am

So what did you do with all the sparks that come of the chop saw....?

I caught mine in a jar and use them to light the hallway.

They also make good garden lights to see my way back to the house.

Have fun by all means....

Hal

Ceramite · Post by **Ceramite** » Fri Jun 10, 2005 10:04 am

Padrig, a step-by-step info guide would be great for the forum!!!!

Padrig · Post by **Padrig** » Fri Jun 10, 2005 10:29 am

Ceramite, I will make some kind of essay when I finally get something that I am satisfied with.

Hal, I use the sparks to give the finishing touch to baby back ribs myself.

Pad

polarbearforge · Post by **polarbearforge** » Fri Jun 10, 2005 10:46 am

A couple more things...

What style of mechanism are you using for the tracking adjustment? It it has a bolt or threads in it, go for fine threads. It'll give more room for adjustment than coarse threads.

While I'm fond of using hammers, using a hammer of anysort to adjust a belt sander is an indication of poor design, imho.

Jamie

Padrig · Post by **Padrig** » Fri Jun 10, 2005 10:58 am

Jamie, about the tracking mechanism. I've found a few and the one that looks the best is to have the shaft for the tracking wheel on a pivot with a bolt adjusting the amount of play. Not sure what you used on your machines. Thanks for the thread tips, I hadn't thought of that.

Pad

Padrig · Post by **Padrig** » Mon Jun 13, 2005 1:29 am

Well, here are the latest pics. IÃ¢â‚¬â„¢ve put everything square in hopes of simplifying assembly. I tried a 2 arm design on the contact wheel to get more rigidity. I am thinking that way you can go with relatively small shaft without scarifying strength. You can also see the tracking mechanism. My questions are:

1)Would Ã‚Â¾Ã¢â‚¬Â

Jeff J · Post by **Jeff J** » Mon Jun 13, 2005 7:58 am

How do you plan to tension it?

Padrig · Post by **Padrig** » Mon Jun 13, 2005 10:44 am

Big spring at the back of the upper arm.

Pad

Halberds · Post by **Halberds** » Mon Jun 13, 2005 10:51 am

I think 3/4" tubing is too small. I would use 1.5" box tubing
Go with the small idler you can always change it after test.

Hal

Padrig · Post by **Padrig** » Mon Jun 13, 2005 10:57 am

Hal, I was thinking about 3/4 solid. I think I will make the vertical arm adjustable. So tubing with solid section inserted. What size would you recommend then?

Pad

Halberds · Post by **Halberds** » Mon Jun 13, 2005 11:44 am

Square tubing has some standard sizes that telescope together.
I would go no smaller than 1.5 for the main frame with 1.25 for the telescoping piece.

You could weld some heavy 1/4 hex nuts to the outside piece. Now two bolts can set your telescoping piece rather secure.

Hal

Jacob · Post by **Jacob** » Mon Jun 13, 2005 12:32 pm

Bring the vertical arm foreward so that the front of the belt is vertical. It will throw sparks and grit down instead of at your shoes. The farther you get from the motor, the more friction you can get from the drive wheel. You could also rubberize it. If this is to be your only one, the ability to add a tool rest or platten might be nice. I usually keep them off of my Grizzly, but they're right there if I need them.

Padrig · Post by **Padrig** » Mon Jun 13, 2005 10:13 pm

Jacod, good idea about the sparks. I also plan to make a patten attachment.

Thanks

Pad

polarbearforge · Post by **polarbearforge** » Tue Jun 14, 2005 2:12 am

I agree on going with 1 1/2 " square or bigger for the main upright.

The tracking mechanism will work. What size bolt is that through the tensioning wheel? You'll want 1/2" at the very minimum. Going with grade 5 bolts doesn't hurt either.

I think that you're about at the build and see what happens stage.

Jamie

Halberds · Post by **Halberds** » Tue Jun 14, 2005 2:41 am

Yes Polarbearforge, He will see...... At least he has a wimpy girly motor.
He can't get hurt too bad. Can he?.... You should know..... running a 7HP buffer.

Pad, you will be needing after your structural test a TEFC 1 to 1.5 HP motor.
(Totally Enclosed Fan Cooled)

Hal

Ps: Thanks for the progress pics.

Padrig · Post by **Padrig** » Tue Jun 14, 2005 1:02 pm

Hal, I am waiting for a TEFC 1 hp motor. That is also why I can not start construction yet. The motor doesnt have the same specs (shaft size, height) as this one and I am just not good enough to figure out the measurements without it.

The friend who is sending me the motor is also helping me with a design for the drive wheel that would use a "taper lock" bushing since I dont have a way to cut a keyway in the wheel.

So the wheel you see is also just a steel mock-up. I will probably make the real one a smidgen bigger diameter and AL.

So when you guys say 1.5 tubing for the upright I means 1.25 full bar sliding in it? That'll be strong.

Thanks again for all your help. Couldn't do this with all your help. Well I could but it would blow up in my face in a hurry.

Pad

What do you think of my design? (Sander) UPDATE

What do you think of my design? (Sander) UPDATE